Welding electrode coating composition



1 6 8 1 REFERENCE Patented Sept. 23, 1947 -:.-uNlTEo5 sTArl:-s PATENT OFFICE 'EWEILDING ELECTRODE COATING T COMPOSITION Carl Jonathan Hirschler, New Malden, end william George Campbell, Aylesbury, England No Drawing. Application November 13, 1944, Serial No. 563,318. In Great Britain November 2 }laims. (61.219-8) "l 1 e 2 This invention relates to cellulosic material nished with a coating composition as defined in and to welding electrode coating compositions the preceding paragraph. containing the same and welding electrodes coat- The following particulars are given by way of ed with such compositions. example to illustrate suitable methods of car- As at present manufactured the coating of 5 rying the invention into effect: shielded welding electrodes contains as an important ingredient cotton flock or other form of Example I comminuted cellulose. 10 1b dr 50 e y -mesh spruce woogiolg 1s 9 (Meet of the f f the incorporated with a 5 per cent. (weight/volume) ductlon of a cellulosic material WhlCh can be l0 aqueous Solution of hydgochloric acigam the used wlth advamalge the coatmg of welding portlon of 1 gallon of solution per pound of wood electrodes in substitution for a part or the whole noun The mixture is boflgg t atmospheric presof the flock or other form of cellulose which sure for two hours. t been used thls 'purpcfsei fmher Thereafter the solid product is isolated by filob ects being the productlon of coating compo- 15 nation, washed with 0 water until free from sltlons for electrodes and electrodes fiurnished acid -ma constant weight at 100 to 333.22%.ffi fifiitis itfijiiiii a f is din in an end-runner mill to ve a wder flour or other s ntably commlnuted llgnmk ga of passing a 120 meSh Saree? p0 Ealm cellulosic material to In the treatment as above described of wood W5. e Se proquc flour which was found by analysis to contain a, he residual matenal m gnm 252 percent. of lignln the finished product condeslred avergge t' f" taining 36.3 per cent. and the complete process In thls way a product 15 obtiamed wmch of had the effect of lowering the absorbency tot i and 26 wards liquid water as found by a standard testporn 9 h 1 i t e s gwmi s a ing procedure from a value of 6 ml. per gramme M an t e hgmfi? matem' in the case of the original wood fiourto 2.8 ml. w c l W1 1 be appreciated ls of advantage from per gramme m the finished product the polnt of view of the use of the material in electrode coating compositions, as it is known 30 Example II that the pyrolysis of cellulose gives rise to acrid 245 1b f 10 mesh spruce sawdust con fumes which are articular] obect'onable hen 9 Wm, p y J 1 w taining 32 lb. of water as molstfiie of condition shielded welding electrodes ar used in onfin d spaces. 6 c e is incorporated with 148.5 gallons of later and The treated material furthermore has a su- 35 336 of hydrochloric acid of The perior affinity toward silicate solutions which is We 15 i aimospfii'ryfiessure attributable t ub t EEFQEH -gffgFE com hours. "I'Ke solid product is thereafter'isolated tent, by filtration, washed with hot water until free In other words the reduction of the cellulose from acid and (121.953. to constant weight .1 content of the material which is effected by the 40 to ,957-.2; The dried Product Z-QHFQ to treatment in accordance with the invention has W ew screen o a mp a t the effect of effecting a reduction in the producthorough mlxmg 20 tunes Its welght M tion of acrid fumes and maintaining or increasfined and on a filter under ing the extent to which a. given quantity of the msphenc Pressure retains not more than three product can retain a silicate within the coating timesfi's p weight of waterof the finished electrodes without depriving the a I product of its other desirable properties. E2 mple H A coating composition in accordance with the 245 lb. of air-dry IO-mesh gruce sawdust coninvention consists in li ii-containing cellulosic taining ,32 lb. of water as moisture of condition material obtained in m ove spec I 60 is incorporated with 121 gallons of the spent acid in association with appropriat inding gents liquor removed by filtration and prior to wash and other essential and any desira 1e cons l umom a previous cook as in Example 11 above, ents of the coating compositions previously em- 112 1b. of hydrochloric acid of 28 Tw. and 47 ployed for the like purpose. gallons of water. The mlifture ls Dolled for two The invention also consists in electrodes furhours at a'tm' ospherlc pressure and the solid 3 product isolated, dried and ground as in Example H.

We have found that in continuous production the procedure indicated in Example III may with advantage, as regards economy of acid, be followed until .four batches of 245 lbs. of ,sawdust have been so treated. In practice lignin contents ranging from 36 per cent. up to and including 40 per cent. have been obtained.

Example IV This example relates to the use of hydrochloric acid of 20 per cent. concentration, a solution mm which, after use, hydrochloric acid can be To a mixture within this range of compositions there is added an appropriate proportion of a sodium or potassium silicate solution of the speafic gravity abdv e statd'to yield a mass 5 capable of being extruded.

Electrodes in accordance with the invention are produced by extrusion of the composition through a die through which also the welding .electrodes are passed.

It is to be understood that our invention is ,inno way confined to the above examples and variations may be made. Thus both the concentration of acid and time of boiling may be waried and also the fineness of grinding of the recovered for re-use by distillation. lbs. of end product and in the constitution of the coatair-dry B Spruce dilo l ing composition.

rated with a per cniflwe'i'glitfiolume) solution of hydrochloric acid in the proportion of 0.85 gallons of solution per pound of wood flour.

We claim: vl. A coating composition for welding electrodes comprising ligno-cellulosic material, the lignin The mixture is boiled for two hours at atmos- 20 gpngfituting from about 3 percent t '70 percent pheric pressure in a closed vessel fitted with a reflux condenser. After removal of the spent liquor containing soluble decomposition products of the wood the solid product is washed, ged andgrgund as in Examples 11 and III above. this way a material of 65 to 70 per cent. lignin content may be obtained.

We have .found that when incorporated with sodium or tassipm silicate solution of specific gravity of a out 1.36 so as to form a composition 3 silicate solution. The corresponding .average figure for the air-dry product prepared as in Example IV above was 6.3 and for powdered cotton cellulose of similar particle size it .was

The following is an example of a coating com- 40 position for welding electrodes within the scope of the invention:

Per cent by weight Titanium dioxide or ;rutile 201-40 Ferromanganese 15-25 Lignin-containing cellulosic material. 30- Felspar or other silicates "Remainder thereof, and a binding agent.

2. .A coating composition for welding electrodes comprising ligno-cellulosic material, the lignin constituting from about 36 percent to percent thereof, and an alkali metal silicate solution as a binding agent, the silicate solution amounting to between about 4.69 and 6.3 times the weight of the Jigno-cellulosic material, said solution havi aspecific gravity of about 1.36.

CARL JONATHAN HIRSCI-ELER. WILLIAM GEORGE CAMPBELL.

,REFERENCES CITED The following references are .of record in the :file .of this patent:

HNI E ST ES P T T Number Name Date Re. 22,29 5 Olson Mar. 30, 1943 1,885,715 .Jerabek (l) Oct. 25, 1932 52,086,132 Jerabek (2) July 6, 1937 2,209,829 :Rasmussen et a1. July 30, 1940 2,269,665 -Herbst Jan. 13, 1942 

